passive solar greenhouse question

Hello Permie People!!

Im new to the forum... well to the posting side... ive been a lurker for years! lol And would like to give everyone a big heartfelt thank you for all of the great info, tips etc you all rock!

OK.. on to my question..... the image above is a sketch up pic of the passive solar greenhouse im building... just got it under roof. IM a glass blower by trade but am a recovering union carpenter ( former life) and have always been interested in alt construction. And this is my attempt to play with some of the useless knowledge that ive accumulated over the years.

Since this is sort of an experimental building (to me) and with the possibitly of selling in the next 10 years I opted to stay in the convention construction material realm.... for resale reasons etc... ( not everyone can see beauty in earthen walls like I do) The building 20x20 sits on a hillside, the foundation on the front portion( greenhouse) is about 5-6 foot deep ( concrete block- sealed), the back 6 foot is more of an enclosed pole building style to house some milking goats (nigerian dwarfs) and a work/ milk bench. The building is insulated with rock wool and the face is exposed cedar with solex covering.

Im planning an aquaponic set up and rocket mass heater ( which im sure ill be back on here asking questions for)

Her eis the question finally.... im sort of stuck at the moment and could use some recommendations/ ideas. Im not sure what to do on the interior greenhouse insulated walls... being im expecting humid air and the mass heater heat etc Some of the solutions ive been thinking about would be... plywood with a white pond liner on the outside ( drawbacks- plywood in a wet area scares me and not sure how it would look), ive seen all sorts of plastic, vinyl wall board solutions but most are pricey and would like to avoid adding more plastics to the mix if possible. Being an artist i had a vision of some sort of concrete art adorning the back wall... not sure if i can do a vertical concrete face over plywood/ drywall etc or perhaps a tuffa? or how it would hold up.

But any ideas would be appreciated .... perhaps this has been addressed elsewhere? or one of you have a magical solution?

Thanks in advance for the time taken to read through this and possibly helping!

I think i got enough info in there let me know if i missed something... ive been doing a time lapse of the building ill share when complete if interested.
thanks again!

Hardieboard siding.

When I bought my fixer-upper, the wood siding had a lot of water damage from our rainy climate. I decided to take it off and replace it with Hardieboard siding, the lap siding type. I know that it is not the greenest material to be using (being cement and all), but there is no humidity or rain-splashing problem to worry about.

I put up a seasonal greenhouse on the southwest exposure of my house in the fall and take it down in the spring, and the Hardieboard that makes up the greenhouse back wall is indistinguishable from that of the other exterior walls.

John has the right idea! hardieboard is a great product for the application. There is also a product called fiberock which is also used in bathrooms.

Thank you both so much for taking the time to reply!!

I actually scored some hardie plank siding from craigslist for the exterior. The only problem i have with it for the interior is its not rated to be hung on a ceiling .... and was looking for a solution i could use on the wall and continue up the ceiling. IM unfamiliar with fiberrock.... ill have to look into that.... curious if thats what they call greenboard?

thank you both!!

Green Board is a gypsum product, it has been treated for water resistance.
Fiber rock is a silicon based product, very stable and should be cut with a diamond blade, the dust is not good to breathe so a respirator is a must.
Hardyboard is an air infused product most suitable for floors and walls.

What the Amish use is metal siding/roofing, inside and out.

If you don't mind a lot of extra work, how about lime plaster over metal lath? The lime will keep mold from growing on the surface and you can let your creative juices flow by creating cornaces and other 3D relief objects, curved walls, and recessed owlcoves. Anyone ever use lime plaster in a greenhouse?

Thanks all for the ideas.... I found a decent source for cement board which im leaning toward, and already have rock wool insulation on site for the walls. But was thinking about a plaster/ vertical cement over it (thinking of a sculpted tree on the wall etc etc) However Im curious as to the mix I will need , being that ill have a rocket mass heater along that wall and curious about cracking.

any of you do a plaster or vert concrete mix in a greenhouse?

thank you all again!